外温变化下小鼠肝细胞18s rRNA降解与死亡时间关系研究

目的探讨在外界环境温度变化条件下,小鼠肝细胞18s rRNA降解与死亡时间的关系。方法小鼠断颈处死后置于10℃、15℃、20℃、25℃、和30℃温度下保存;从死后6h至72h,每6h分别提取肝细胞组织中总RNA。利用实时荧光定量PCR检测18s rRNA循环阈值(Ct值)的变化。应用插值函数进行分析拟合,建立死亡时间推断方程。结果各温度组Ct值随死亡时间延长均呈上升趋势,对所得数据进行插值拟合,得到一定温度变化区间内(10℃~30℃),Ct值变化与PMI关系的三元五次曲面方程:f(x,y)=-426.9+30.82x+44.48y-1.297x~2-1.837xy-1.388y~2+0.034 38x~3+0.038 17x~2y+0.038 67xy~2+0.028 77y3-0.000 612 9x~4-3.897e~(-7)x~3y-0.001 223x~2y~2+0.000256 6xy3-0.000 537 4y~4+3.606e~(-6)x~5-2.846e~(-6)x~4y+1.009e~(-5)x~3y~2-3.439e~(-6)x~2y3-2.556e~(-7)xy~4+2.664e~(-6)y~5(r2=0.999 4)。结论在外界温度变化条件下,小鼠肝细胞18s rRNA降解与死亡时间关系符合三元五次方程分布,利用插值函数拟合的方法可在外界环境温度变化条件下进行死亡时间推断。     

地西泮及去甲地西泮在大鼠体内的死后再分布研究

目的观察地西泮及其主要代谢物去甲地西泮在大鼠体内的死后再分布特点。方法大鼠24只,随机分成8组,以安定90 mg/kg灌胃,2 h后脱颈椎处死,左侧卧位,分别置于室温(10℃)条件下,于死后不同时间(0h、2h、4h、8h、12h、24h、48h、96h)取心、肝、脾、肺、肾、大脑、肌肉,固相萃取、高效液相色谱法检测其中地西泮及其主要代谢物去甲地西泮的含量。结果地西泮及其主要代谢物去甲地西泮在染毒处死大鼠内各时间点、各脏器都有分布并呈现出一定的规律性。结论地西泮及其主要代谢物去甲地西泮在染毒处死大鼠内可发生死后再分布。     

猪肋软骨和肋骨的ATR-FTIR光谱变化与死亡时间的关系

目的应用衰减全反射傅里叶变换红外(attenuated total reflection-Fourier transform infrared,ATRFTIR)光谱技术分析长白猪死后肋软骨和肋骨组织随死亡时间推移的化学降解过程,为死后较长时间段内推断死亡时间提供可行的新途径和方法。方法猪放血处死后取肋软骨和肋骨离体置于20℃环境,后每72 h提取部分组织样本,进行ATR-FTIR光谱分析,并与对应死亡时间点进行相关性分析。结果随死亡时间的延长,肋软骨与肋骨FTIR的主要吸收峰峰位没有发生明显变化,而其部分峰强比出现了不同时序性的变化趋势,并与死亡时间存在良好的相关性,肋软骨较肋骨组织有更好的时序性。结论应用ATRFTIR光谱技术发现死后猪肋软骨和肋骨组织光谱学变化存在一定的规律性,有望成为基于光谱学推断死亡时间的一种新途径。     

The leadership dilemma: Examining the impact of strong leaders on parties

Party leaders are often regarded as crucial to a party's success. Successful leaders tend to be big personalities who dominate their party's organisation, policy development and electoral campaigns. But does that control come with a price? We test to see if such leaders damage their parties in the medium term. This happens because strong leaders might be ceded too much control of the party organisation, policy and electoral strategy. We specifically hypothesise that political parties will go through a period of leadership instability and electoral decline after strong leaders step down. Using a dataset with elections under party leaders in nine countries over a 25-year period, and a qualitative case study, we find some evidence for the theory, which should prompt further research of the question.     

Determination of season at death using dental cementum increment analysis

Dental cementum anchors teeth into their sockets via the periodontal ligament. In mammals, dental cementum is laid down in alternating opaque and translucent bands representing winter (dormant) and summer (growth) seasons. Each pair of bands represents 1 year of life. Estimates of age at death based on counting pairs of bands are highly accurate. If the timing of the transition between winter and summer bands could be identified in humans, dental cementum increment analysis could be used to specify the season at death. This pilot project attempts to determine when these transitions occur and thus provide forensic anthropologists with a technique that would refine our estimates of postmortem interval. Extracted teeth were obtained from a local oral surgeon, embedded, sectioned, ground, polished, and examined under transmitted polarized light. The outermost increment was identified and measured along with other randomly chosen like bands. A transition from translucent to opaque bands was observed in teeth extracted in early October, while teeth extracted in early April exhibited nascent translucent bands. Further, significant correlations were observed between band thickness and number of days into either season, suggesting that band width increases as either season progresses. In this blind study, extracted teeth were effectively sorted into the spring/summer or fall/winter season 99% of the time.     

Olanzapine‐Induced Fatal Ketoacidosis with Pneumomediastinum and Subcutaneous Emphysema

We report a case of fatal olanzapine‐induced ketoacidosis in which pneumomediastinum (PM) and subcutaneous emphysema (SE) were detected on postmortem computed tomographic (CT) images. A man in his forties was found in a state of cardiopulmonary arrest with profuse perspiration, and 50 empty capsules of olanzapine (10 mg) and flunitrazepam (1 mg) were found in his room. The major findings of postmortem CT prior to autopsy were PM and SE from the lower half of the face to the height of the first rib. The results of autopsy, biochemical tests, and toxicological analyses indicated the cause of death to be fatal ketoacidosis induced by olanzapine intoxication. No injuries, medical interventions, or particular diseases were evident, suggesting that PM and SE were caused by ketoacidosis. Our findings indicated that toxicological analyses should be performed when PM and SE are detected on CT images.     

Cannabinoid Hyperemesis Syndrome: Reports of Fatal Cases

Cannabinoid hyperemesis syndrome (CHS) is one of the more clinically challenging effects of cannabis consumption. It is characterized by cyclic attacks of nausea and vomiting in chronic cannabinoid users and learned behavior of compulsive hot bathing. The deaths of a 27‐year‐old female, a 27‐year‐old male, and a 31‐year‐old male with a history of CHS are reported. The decedents had a history of cyclical nausea and vomiting, chronic cannabinoid use and negative laboratory, radiological and endoscopic findings. All presented to the emergency department with nausea and vomiting in the days preceding death and were treated symptomatically. Toxicological analysis revealed tetrahydrocannabinol in postmortem blood. The cause of death of two of the three cases was attributed to CHS. CHS was appreciated in the third case but was not the cause of death. These three cases demonstrate the importance of recognizing CHS as a potential cause or contributing factor to death in cannabinoid user.     

Citrate Content of Bone as a Measure of Postmortem Interval: An External Validation Study

The postmortem interval (PMI) of skeletal remains is a crucial piece of information that can help establish the time dimension in criminal cases. Unfortunately, the accurate and reliable determination of PMI from bone continues to evade forensic investigators despite concerted efforts over the past decades to develop suitable qualitative and quantitative methods. A relatively new PMI method based on the analysis of citrate content of bone was developed by Schwarcz et al. The main objective of our research was to determine whether this work could be externally validated. Thirty‐one bone samples were obtained from the Forensic Anthropology Center, University of Tennessee, Knoxville, and the Onondaga County Medical Examiner's Office. Results from analyzing samples with PMI greater than 2 years suggest that the hypothetical relationship between the citrate content of bone and PMI is much weaker than reported. It was also observed that the average absolute error between the PMI value estimated using the equation proposed by Schwarcz et al. and the actual (“true”) PMI of the sample was negative indicating an underestimation in PMI. These findings are identical to those reported by Kanz et al. Despite these results this method may still serve as a technique to sort ancient from more recent skeletal cases, after further, similar validation studies have been conducted.     

Sudden Death from Cardiopulmonary Arrest on Arrival of a Patient with Pulmonary Tuberculosis: A Case Diagnosed by Postmortem CT and Autopsy

Sudden death due to massive hemoptysis during management of tuberculosis occurs in a considerable number of patients. However, when massive airway hemorrhage occurs in a patient in whom tuberculosis has not been confirmed and a blood is not apparent externally on the face/body, it is difficult to immediately identify the cause of death as airway obstruction by tuberculous bleeding in the airway. We encountered an 83‐year‐old Japanese woman with her medical history included treatment of tuberculosis in her 20s who was in cardiopulmonary arrest on arrival (CPAOA), and the cause of sudden death could not initially be identified. Postmortem CT (PMCT) and autopsy revealed that the cause of sudden death was airway obstruction/asphyxia by tuberculous massive airway hemorrhage. Identification of the cause of death facilitated a subsequent active contact investigation and led to prevention of secondary tuberculosis infection.